FORT LAUDERDALE, Fla. — A memorable season capped by a super title game with a record TV audience has NFL executives and fans beaming.

The smiles might soon disappear.

Pro football is headed into the great unknown. Barring a quick — and totally unexpected — agreement with the players' union on a new contract, 2010 will have no salary cap. After that, perhaps a work stoppage, something NFL Players Association executive director DeMaurice Smith puts at "14" on a scale of 1 to 10.

Commissioner Roger Goodell doesn't agree, believing negotiations will lead to a new deal before March 2011, when the collective bargaining agreement expires. But an accord before the New Orleans Saints — who dat? — begin defense of their Super Bowl championship in September is unlikely.

The 32 team owners clearly are prepared for a go at the first uncapped season since 1993. Enough restrictions are in place, including extending the minimum years of service for unrestricted free agency from four years to six, that baseball-like bidding wars are improbable.

With the owners claiming they are losing millions and the players arguing that teams are making money by the fistful, a common ground will be difficult to find.

Free agency begins March 5. The more critical date might be March 5 of next year, when, if no new deal has been struck, the most popular and prosperous sport in America could see the owners locking out the players.

That's the last thing fans want to hear after a special season featuring the Saints capping a football renaissance for their team and their city with their first Super Bowl title. The NFL's best teams, led by New Orleans, generally have become the most potent on offense: each division winner except Cincinnati regularly visited the end zone, and three of the four playoff semifinalists scored at least 416 points.

And as some stars begin to fade (LaDainian Tomlinson, Champ Bailey), others emerge (Chris Johnson, Darrelle Revis). A league driven by quarterbacks has a splendid blend of veterans in top form (four-time MVP Peyton Manning, Super Bowl most valuable player Drew Brees, even 40-year-old Brett Favre), passers only now in their primes (Philip Rivers, Ben Roethlisberger, Aaron Rodgers), and youngsters with great promise (Matt Ryan, Joe Flacco and Chad Henne).

Not that defense has disappeared, particularly in New York with the Jets, Baltimore, Cincinnati and Dallas. All of them made the playoffs in '09.

Keeping those established and rising stars healthy will be a key issue after the league, the teams and the NFLPA ramped up prevention and treatment of concussions. Even Congress has gotten involved.

"I think concussions have been a major focus in the league for several years, and we need to make sure we continue to do what we can to make the game safer," Goodell said. "And that deals with how we modify the rules and take certain techniques out of the game; how we use the better equipment to make sure that our players are safer; and what we can do to make sure that our coaches and our players understand the serious nature of these injuries, and that they get medical help as soon as an injury occurs."